The mobility afforded by wireless communication networks has resulted in increased usage of such networks. Private wireless networks and cellular networks are two common types of wireless communication networks. Private wireless networks, also known as wireless local loop (WLL) networks, are commonly operated by public safety agencies, taxi services and delivery services. Private wireless networks typically operate over a limited range of frequencies and within limited geographic areas. In contrast, cellular networks typically operate over a larger number of frequencies and provide coverage over larger geographic areas.
Although conventional cellular networks may provide sufficient reliability for the average user, there are a number of deficiencies which prevent widespread adoption by public safety agencies. For wireline communication, public safety agencies can be provided with dedicated circuits and switches such that even when the Public Switched Telephone Network (PSTN) is overloaded with non-emergency traffic, communications between, and within, public safety agencies can still be completed. To provide reliability to wireless communications, public safety agencies typically employ private wireless networks which operate over frequencies reserved for public safety agencies.
Although these private radio networks reduce the likelihood that calls by public safety agencies are blocked from accessing the radio network, they are expensive to implement and maintain. For example, these networks typically require the use of specialized mobile stations which are more expensive than typical mobile stations, due to the relatively low demand for the specialized mobile stations compared to that of mass-produced mobile stations. As used herein, the term mobile station is intended to encompass any type of wireless communication device including wireless telephones, wireless Personal Digital Assistants (PDA), wireless pagers, portable computers with wireless modems and the like. Compared to cellular networks, private wireless networks are more likely to have dead spots where a radio signal cannot be received by the public safety agency worker's mobile station. These dead spots can be extremely hazardous to the public safety agency workers, e.g., a police officer requesting backup, and to the citizenry in general, e.g., a public safety agency worker requesting an ambulance or fire trucks.
One solution currently employed by cellular network operators to encourage use of their networks by public safety agencies is to provide public safety agencies priority access to traffic channels. This typically involves mobile stations used by public safety agencies transmitting a priority indication to the cellular network during a traffic channel request. The cellular network recognizes the priority indication and will grant the public safety agency worker's mobile station access to the first available traffic channel. In some cellular networks when there are no available traffic channels, the cellular network will drop an existing call to make available a traffic channel for the public safety agency worker.
Although these conventional techniques provide public safety agency workers with priority access to traffic channels, they do not address the ability of the public safety agency worker to request access to the traffic channels during periods of congestion on the network. Accordingly, it would be desirable to provide methods and systems for reducing the time, and increasing the likelihood that, traffic channels are granted to public safety agency workers.